Figure 1.
Mitochondrial genomes for the three taxa sequenced as part of this study.
A. Appalachioria falcifera. B. Abacion magnum. C. Brachycybe leconti. The grey region corresponds to the A-T Rich Region (the origin of transcription and replication). The red sequences depict the ribosomal subunit DNA. The green regions represent protein-coding sequences. The pink regions correspond to transfer RNAs.
Figure 2.
Myriapod mitochondrial genome syntenies depicted in a phylogenetic context.
The phylogeny is adapted from Regier and Shultz [18] and Sierwald and Bond [6]. Grey regions are ribosomal subunit genes, white sequences code for transfer RNAs, and black region depicts major A-T Rich region in each genome. The other regions are protein coding; the color scheme is used in subsequent figures.
Figure 3.
Amino acid conservation values based on identity for each of the 13 protein-coding regions of all currently available myriapod mitochondrial genomes.
Figure 4.
Paiwise comparisons of total mitochondrial protein-coding amino acid percent identity for all myriapod taxasequenced to date.
These data show that, overall, taxa do not have high levels of conservation in mitochondrial amino acids sequences. The most similar taxa are the two centipedes of the order Lithobiomorpha and family Lithobiidae, Lithobius forficatus and Bothropolys sp.
Figure 5.
Phylogenetic trees for the Myriapoda and Ecdysozoa based on mitochondrial protein-coding genes.
The following phylogenies were reconstructed using maximum likelihood and Bayesian inference of amino acid sequences. The ML trees were obtained using RAxML with 1000 random addition searches followed by 1000 boostrap replicates. The BI trees were obtained from two phylobayes runs consisting of 10000 cycles. The first 2000 cycles were discarded as burn-in. A) Myriapod ML tree, B) myriapod BI tree, C) ecdysozoan ML tree, and D) ecdysozoan BI tree. In the myriapod trees, millipedes taxa are colored green, symphylans are blue, and centipedes are red. In the ecdysozoan trees, outgroup taxa (non-arthropods) are colored black, myriapods are green, chelicerates are red, “crustaceans” and non-insect hexapods are blue, and insects are yellow.
Figure 6.
PhyDesign results for all 13 protein-coding mitochondrial gene regions.
The peaks for each gene region skewed toward the terminals of both trees. As a result, most signal deep in the trees is confounded by noise. A) Myriapod BI tree converted to ultrametric. B) Ecdysozoan BI tree converted to ultrametric. These results indicate that mitochondrial protein-coding sequences are not appropriate for reconstructing deep arthropod relationships, even when the data is encoded as amino acid residues. The color scheme follows figures 2 and 3.
Table 1.
Taxonomy and locality data for the specimens sequenced herein.